1000kV交流绝缘子串泄漏电流特性研究

Research on 1000 kV AC Insulator leakage Current Characteristic

为研究特高压交流输电线路绝缘子的耐污性能,在试验室试验采用GB/4548-2004规定的升降法进行人工污秽试验。研究1000kV3种不同型式的交流绝缘子在u50%人工污秽放电过程中的泄漏电流变化特性。它们在相同附盐密度SDD条件时的泄漏电流峰值变化趋势一致,但幅度差异较大,其中8m空心绝缘子泄漏电流峰值幅度最高,支柱绝缘子次之,盘形绝缘子泄漏电流峰值幅度最低,主要与其结构形式有关。1000kV输电线路用盘形绝缘子临近闪络时泄漏电流的临界电流Ic值为500mA,明显小于500kV长串绝缘子闪络的临界电流值Ic水平;而超过一定幅值的电流脉冲频度明显大于500kV长串绝缘子的电流脉冲频度水平。反映出1000kV特高压污秽绝缘子电弧发展更迅猛、更强烈的特点。记录绝缘子超过一定幅值的电流脉冲计数的变化、泄漏电流波形的改变、以及峰值幅度数据的分析结果,指出了绝缘子闪络与否的条件。特高压绝缘子泄漏电流峰值Im幅度、电流波形及电流脉冲放电频度可作为污闪报警的判据。

To study insulator anti pollution performance of UHV AC transmission line, artificial pollution test is done using up-and-down way provided by GB/4548-2004 in lab. Study three 1000 kV different style AC insulators, and record and analyze leakage current variety characteristic in the process of u50% artificial pollution discharge. The variety of leakage current peak value is accordant, but the difference of range is big, and the 8 meter hollow insulator leakage current is biggest, column-type insulator is second, is lowest. The leakage current critical current Iois 500 mA when 1000 kV discoid insulator is near flashover, which is less than that of 500 kV long bunch insulator. Current pulse frequency is markedly bigger than that of 500 kV long bunch insulator. Test results indicate it very swift and violent that 1000 kV UHV nastiness insulators electric arc. Record insulator current pulse count variety, change of leakage current and peak data, indicates the factor of insulator flashover. This paper shows it as criterion of pollute flashover alarm that UHV insulator leakage current peak value.